[WIP] feat: Shared memory for multi-agent (cross-agent)

[quangdang46]

Gap #19 — Medium

Cross-agent data sharing during coordinated workflows.

Approach: Extend mempalace_rust coordination module

mempalace_rust already has coordination/ with SignalStore, LeaseStore, Team, Mesh, ActionStore, CheckpointStore, RoutineStore, Frontier, and 20+ MCP tools.

6 features to add in mempalace_rust first:

• mempalace_rust#37 — Live delivery (inject into idle agents)
• mempalace_rust#38 — Event sourcing (replay/crash recovery)
• mempalace_rust#39 — File reservations (exclusive/shared locks)
• mempalace_rust#40 — Saturation signals (detect coordination problems)
• mempalace_rust#41 — Artifact handoff (large payloads)
• mempalace_rust#42 — Two-phase claim (race prevention)

Then jcode integration:

• Extend jcode-mempalace-adapter with coordination adapter
• Register 8 new tools
• Wire live delivery + saturation into agent turn loop

Full Plan

docs/mempalace-shared-memory-master-plan.md